THE DELTA-WYE APPROXIMATION PROCEDURE FOR 2-TERMINAL RELIABILITY

The Delta-Wye Approximation Procedure (DWAP) is a procedure for estima ting the two-terminal reliability of an undirected planar network G = (V, E) by reducing the network to a single edge via a sequence of loca l graph transformations. It combines the probability equations of Lehm an - whose solutions provide bounds and approximations of two-terminal reliability for the individual transformations-with the Delta-Wye Red uction Algorithm of the second two authors - which performs the corres ponding graph reduction in O(\V\(2)) time. A computational study is ma de comparing the DWAP to one of the best currently known methods for a pproximating two-terminal reliability, and it is shown that the DWAP p roduces approximations that are between 10 and 80 times as accurate.